Allow duck ai chat syncing (Internal)

[CDRussell]

Task/Issue URL: https://app.asana.com/1/137249556945/project/488551667048375/task/1212450128487247?focus=true

Description

Enables duck AI chat syncing for internal builds.

For testing, will require 2 or more devices/emulators, and each will need to be configured to hit duck chat internal config, details below.

Setting up for testing (do on each of the test devices)

• Fresh install internal build type from this branch
• Type ai.duckduckgo into the omnibar, and authorise yourself by signing in
• When prompted, choose the blue button PRODUCTION - setup and go to duck.ai
• Tap Agree and Continue when duck ai chat launches
• You should see a INTERNAL badge
• 🔁 Repeat for your other test device

Steps to test this PR

Logcat filter: message~:"DuckChat-Sync|getAIChatNativeConfigValues"

Syncing some chats between devices

Pre-requisite - set up sync between the two test devices

• On Device A, set up sync Settings -> Sync & Backup -> Sync and Back Up This Device to completion
• On Device A still, choose Sync With Another Device and choose Copy Text Code
• On Device B now, go to Settings -> Sync & Backup and choose Sync With Another Device. Tap Manually Enter Code and Paste Code.

This should set up Device A and Device B to sync with each other.

Test steps

• On Device A, open duck ai chat and start a chat
• On Device B, open duck ai chat and wait a few seconds; verify the chat syncs over
• On Device B, start a new chat
• On Device A, open duck ai chat and wait a few seconds; verify the chat syncs over so you now have 2 chats on each

Native fire button

• On Device A, visit native app Settings -> Data Clearing and enable Clear Duck.ai Chats
• On same device, use the native fire button to clear data and let it restart. Verify duck ai chats are gone.
• On Device B, open duck ai chat and verify the chats are deleted (might take 10-15s)

Validate feature flag gates feature

• Disable aiChatSync feature flag on Device A. Kill app and re-open.
• On same device, open duck ai chat, and verify in the logs that "supportsAIChatSync":false
• On same device, create a new chat.
• Open duck ai chat on Device B and verify the chat does NOT appear
• Re-enabled aiChatSync. Kill app and re-open.

#### Testing when sync is disabled

• On any device, disable sync by Settings -> Sync & Backup -> Turn Off Sync & Backup...
• On same device, open duck ai chat
• Open duck ai settings using overflow (top-left) -> Settings
• Verify you see a button to Set Up Now. Tap it, verify you are taken to sync setup. Hit back button and verify you still see the Set Up Now button.
• Tap it again, and this time set up sync (can just use Sync and Back Up This Device).
• Once sync is set up, tap back to return to duck ai; verify Set Up Now button disappears (might not be immediate)

---

Note

Enables AI Chat sync by wiring JS↔native messaging, storage, and sync service support.

• Adds supportsAIChatSync to getAIChatNativeConfigValues and logs config
• New JS handlers: encryptWithSyncMasterKey, decryptWithSyncMasterKey, setAIChatHistoryEnabled, sendToSyncSettings/sendToSetupSync (open Sync setup), plus Sync-side getScopedSyncAuthToken and getSyncStatus
• Introduces Base64 URL-safe helpers for payload encoding/decoding
• Repository/DataStore: persist DUCK_CHAT_BACKGROUND_TIMESTAMP and DUCK_CHAT_HISTORY_ENABLED with setters/getters
• DuckAiChatDeletionListenerImpl: persist background timestamp; DuckChatSyncDataManager: gate deletions on feature flag and chat history setting
• Sync service: add POST /sync/token/rescope (scoped token), deleteAiChats tests, change dev URL to sync-staging.duckduckgo.com, and new messaging dependencies
• Comprehensive unit tests for new handlers, data manager, and service changes

^{Written by Cursor Bugbot for commit 59d202c. This will update automatically on new commits. Configure here.}

[CDRussell]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• Allow duck ai chat syncing (Internal) #7377 👈 (View in Graphite)
• Extend sync crypto to support byte arrays #7375
• Include duck AI chat deletions in sync engine #7354
• Update sync APIs to support deletions #7340
• develop

This stack of pull requests is managed by Graphite. Learn more about stacking.